1. Field of the Invention
The present invention relates to a suspension apparatus of a vehicle in which a cushion unit (a hydraulic shock absorber) is provided between a vehicle body and a swing arm.
2. Description of the Related Art
In a conventional suspension apparatus of a vehicle, as described in Japanese Patent Publication No. 59-29468 (JP-B), there is a structure in which a base end portion of a swing arm is pivotally attached to a vehicle body so as to freely oscillate. A wheel is rotatably supported to a leading end portion of the swing arm. A first link is pivotally attached to a portion between the base end portion and the leading end portion of the swing arm. A second link is pivotally attached to a position which is below a pivot point to which the base end portion of the swing arm is pivotally attached in the vehicle body. The first link and the second link are pivotally attached. One end of a cushion unit is pivotally attached to the vehicle body, and another end of the cushion unit is pivotally attached to one of the first link and the second link.
In another conventional suspension apparatus of a vehicle, as described in Japanese Patent Application Laid-open No. 2002-68066 (JP-A), there is a structure in which a base end portion of a swing arm is pivotally attached to a vehicle body so as to freely oscillate. A wheel is rotatably supported to a leading end portion of the swing arm. A first link is pivotally attached to a portion between the base end portion and the leading end portion of the swing arm. A second link is pivotally attached to a position which is below a pivot point to which the base end portion of the swing arm is pivotally attached in the vehicle body. The first link and the second link are pivotally attached. One end of a cushion unit is pivotally attached to the swing arm, and another end of the cushion unit is pivotally attached to one of the first link and the second link.
In the suspension apparatus of the vehicle in accordance with JP-B 59-29468 and JP-A 2002-68066, it is intended to secure a road holding property of a wheel on the basis of a damping property of the cushion unit. However, there is a case that a following characteristic in an elongating direction is deteriorated due to an elongation side damping force. In other words, in the case that a load applied to the wheel (a rear wheel) from the road surface is reduced while running on a road surface gap or braking, the wheel leaves the road surface, so that there is a risk that driving force is reduced and stability of the vehicle is deteriorated.